With an altimeter not properly set to qne an air carrier has an altitude undershoot.

Attributes
ACN	527430
Time
Date	200110
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : zse.artcc
State Reference	WA
Altitude	msl bound lower : 27650 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Dawn
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Flight Phase	climbout : intermediate altitude cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : multi engine
Experience	flight time last 90 days : 195 flight time total : 11000 flight time type : 1500
ASRS Report	527430
Events
Anomaly	altitude deviation : undershoot non adherence : far
Resolutory Action	flight crew : returned to assigned altitude
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

Departed geg with pressurization system in standby mode due to the automatic mode being inoperative (MEL'ed). Climbing out of geg, we were asked what our RVR minimums were in sea. Due to very poor WX in sea (1/4 mi and fog), we passed FL180 without resetting our altimeter to 29.92 (geg -- 30.27) as we were pre-occupied monitoring the pressurization system in the standby mode and preparing for an ILS catiii into sea. Noticed our incorrect altimeter setting after approximately 20 mins. Reset to proper and proceeded normally into seattle.

Original NASA ASRS Text

Title: WITH AN ALTIMETER NOT PROPERLY SET TO QNE AN ACR HAS AN ALT UNDERSHOOT.

Narrative: DEPARTED GEG WITH PRESSURIZATION SYS IN STANDBY MODE DUE TO THE AUTO MODE BEING INOP (MEL'ED). CLBING OUT OF GEG, WE WERE ASKED WHAT OUR RVR MINIMUMS WERE IN SEA. DUE TO VERY POOR WX IN SEA (1/4 MI AND FOG), WE PASSED FL180 WITHOUT RESETTING OUR ALTIMETER TO 29.92 (GEG -- 30.27) AS WE WERE PRE-OCCUPIED MONITORING THE PRESSURIZATION SYS IN THE STANDBY MODE AND PREPARING FOR AN ILS CATIII INTO SEA. NOTICED OUR INCORRECT ALTIMETER SETTING AFTER APPROX 20 MINS. RESET TO PROPER AND PROCEEDED NORMALLY INTO SEATTLE.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.